This is a JavaScript version of the C++ interpreter of COW.
Paste the source code in the program text area and click on execute. An example from the author of the JavaScript program:
OOOMoOmoOMoOMoOmoOMoOMoOMoOMoOmoOMoOMoOMoOMoOMoOMoOMoOMoOMMMmoOMMM MMMmoOMMMMOOMOomOoMoOmoOmoomOoMMMmoOMMMMMMmoOMMMMOOMOomOoMoOmoOmoo mOoMMMmoOMMMMMMmoOMMMMOOMOomOoMoOmoOmooMoOMoOMoOMoOMoOMoOmOoMMMmoO moOMMMMOOMOomOoMoOmoOmoomOoMooOOOmOoMMMmoOmoOMMMMOOMOomOoMoOmoOmoo mOomOomOoMMMmoOmoOmoOMMMMOOMOomOoMoOmoOmoomOoMMMmoOMMMMoOMoOMoOMoO MoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoomOoMMMmoOMMMMoOMoomOo MMMmoOMMMMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMoOMooMOoMOoMOoMoo